Image pickup apparatus and lens unit

ABSTRACT

A first lens unit performing communication with an image pickup apparatus with a first voltage and a second lens unit performing communication with the image pickup apparatus with a second voltage are selectively attached to the image pickup apparatus. The image pickup apparatus includes a controller configured to operate with a third voltage different from at least one of the first and second voltages to output a signal for the communication with the first and second lens units, and a determiner configured to determine the type of the lens unit attached to the image pickup apparatus. The controller is configured to produce, as a voltage of the signal for the communication, from the third voltage, one of the first and second voltages corresponding to a determination result of the determiner.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image pickup apparatus and a lensunit interchangeably attachable to the image pickup apparatus such as aninterchangeable lens.

2. Description of the Related Art

Such a lens unit receives, in a state of being attached to an imagepickup apparatus (hereinafter referred to as “a camera”), power suppliedfrom the camera and performs communication of commands, data and otherswith the camera. However, lens units of different types often operatewith different operation voltages.

Japanese Patent Laid-Open Nos. 07-043773 and 2009-93122 disclose camerasto which multiple types of interchangeable lenses that operate withdifferent operation voltages are attachable. Specifically, the cameradisclosed in Japanese Patent Laid-Open No. 07-043773 is provided withmultiple power sources capable of supplying source voltages respectivelycorresponding to the operation voltages of the multiple types ofinterchangeable lenses. On the other hand, the camera disclosed inJapanese Patent Laid-Open No. 2009-93122 is provided with a circuitcapable of producing source voltages (that is, capable of changing aproducing voltage) respectively corresponding to the operation voltagesof the multiple types of interchangeable lenses.

However, the camera disclosed in Japanese Patent Laid-Open No. 07-043773has a problem that its size becomes large because of being provided withthe multiple power sources having large capacities for supplying thesource voltages to the multiple types of interchangeable lenses.

Moreover, the camera disclosed in Japanese Patent Laid-Open No.07-043773 determines the type of the interchangeable lens attachedthereto on a basis of whether or not the interchangeable lens operatesby a lower one of the multiple (two) source voltages (V1 and V2 lowerthan V1). However, the determination requires that the interchangeablelens originally operating with the source voltage V2 cannot operate withthe lower source voltage V1. In other words, there is a restrictedrelationship between the source voltages V1 and V2. If the cameraerroneously determines that the attached interchangeable lens originallyoperating with the source voltage V1 is one operating with the sourcevoltage V2, the attached interchangeable lens receives, from the camera,the source voltage V2 exceeding its rated source voltage or a sourcecurrent exceeding its rated source current, which causes performancedeterioration or failure of the attached interchangeable lens.

On the other hand, the camera disclosed in Japanese Patent Laid-Open No.2009-93122 determines the type of the attached interchangeable lens on abasis of a reference voltage output from the interchangeable lens to thecamera. Therefore, there is no restricted relationship between thesource voltages of the interchangeable lenses such as the restrictedrelationship between the source voltages V1 and V2 in the cameradisclosed in Japanese Patent Laid-Open No. 07-043773. However, thecamera disclosed in Japanese Patent Laid-Open No. 2009-93122 requiresthe circuit for changing the source voltage to be supplied to theattached interchangeable lens, which also increases the size of thecamera. In addition, the camera is also likely to erroneously determinethe type of the attached interchangeable lens, and thereby supplies, tothe attached interchangeable lens, the source voltage exceeding itsrated source voltage.

BRIEF SUMMARY OF THE INVENTION

The present invention provides an image pickup apparatus enablingcommunication with multiple types of lens units whose communicationvoltages are different from one another without changing a sourcevoltage to be supplied from the image pickup apparatus to the attachedlens unit, and provides a lens unit attachable to the image pickupapparatus.

The present invention provides as one aspect thereof an image pickupapparatus to which a plurality of types of lens units are selectivelyattachable. The plurality of types of lens units include a first lensunit that performs communication with the image pickup apparatus with afirst voltage and a second lens unit that performs communication withthe image pickup apparatus with a second voltage different from thefirst voltage. The image pickup apparatus includes a controllerconfigured to operate with a third voltage different from at least oneof the first and second voltages to output a signal for thecommunication with the first and second lens units, and a determinerconfigured to determine the type of the lens unit attached to the imagepickup apparatus. The controller is configured to produce, as a voltageof the signal for the communication, from the third voltage, one of thefirst and second voltages corresponding to a determination result of thedeterminer.

The present invention provides as another aspect thereof a lens unitincluded in a plurality of types of lens units selectively attachable toan image pickup apparatus that sets a communication voltagecorresponding to the type of the lens unit attached thereto and performscommunication with the attached lens unit with the communicationvoltage. The lens unit includes a mount to mechanically couple with theimage pickup apparatus and to electrically connect the lens unit withthe image pickup apparatus, and a lens controller configured to receivepower supply at a fourth voltage from the image pickup apparatus, toproduce from the fourth voltage a sixth voltage different from thefourth voltage, and to perform the communication with the image pickupapparatus with the sixth voltage. The mount includes a first lensterminal connected with a second resistance having a predeterminedresistance value, thereby enabling the image pickup apparatus todetermine the type of the lens unit attached thereto and to set thecommunication voltage for the attached lens unit on a basis of adetermination result of the type of the attached lens unit.

The present invention provides as still another aspect thereof a lensunit included in a plurality of types of lens units selectivelyattachable to an image pickup apparatus that sets a communicationvoltage corresponding to the type of the lens unit attached thereto andperforms communication with the attached lens unit with thecommunication voltage. The lens unit includes a mount to mechanicallycouple with the image pickup apparatus and to electrically connect thelens unit with the image pickup apparatus, and a lens controllerconfigured to receive power supply at a fourth voltage from the imagepickup apparatus, to produce from the fourth voltage a sixth voltagedifferent from the fourth voltage, and to perform the communication withthe image pickup apparatus with the sixth voltage. The mount includes afirst lens terminal to output a predetermined voltage corresponding tothe type of the lens unit in a state of being attached to the imagepickup apparatus, thereby enabling the image pickup apparatus todetermine the type of the lens unit attached thereto and to set thecommunication voltage for the attached lens unit on a basis of adetermination result of the type of the attached lens unit.

The present invention provides as yet still another aspect thereof alens unit including a mount to mechanically couple with the image pickupapparatus and to electrically connect the lens unit with the imagepickup apparatus, and a lens controller configured to receive powersupply at a fourth voltage from the image pickup apparatus, to producefrom the fourth voltage a sixth voltage different from the fourthvoltage, and to perform the communication with the image pickupapparatus with the sixth voltage. The mount includes a first lensterminal enabling provision of the type of the lens unit by aconfiguration connected with a second resistance having a predeterminedresistance value corresponding to the type of the lens unit.

The present invention provides as further another aspect thereof a lensunit including a mount to mechanically couple with the image pickupapparatus and to electrically connect the lens unit with the imagepickup apparatus, and a lens controller configured to receive powersupply at a fourth voltage from the image pickup apparatus, to producefrom the fourth voltage a sixth voltage different from the fourthvoltage, and to perform the communication with the image pickupapparatus with the sixth voltage. The mount includes a first lensterminal enabling provision of the type of the lens unit by aconfiguration to output a predetermined voltage corresponding to thetype of the lens unit in a state of being attached to the image pickupapparatus.

Other aspects of the present invention will become apparent from thefollowing description and the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are block diagrams showing a configuration of a camerasystem including a camera and an interchangeable lens that areEmbodiment 1 of the present invention.

FIGS. 2A and 2B are block diagrams showing connection of lens typedetermining devices provided in first and second interchangeable lenseswith a camera microcomputer in Embodiment 1.

FIG. 3 is a block diagram showing a configuration of a voltage converterin Embodiment 1.

FIG. 4 is a flowchart showing a communication setting process inEmbodiment 1.

FIGS. 5A and 5B are timing charts showing examples of input and outputtimings of the camera microcomputer in Embodiment 1.

FIG. 6 is a block diagram showing configurations of a camera controllerand a lens controller of a camera and an interchangeable lens that areEmbodiment 2 of the present invention.

FIG. 7 is a circuit diagram showing a configuration of a voltageconverter in Embodiment 2.

FIGS. 8A and 8B are timing charts showing examples of input and outputtimings of a camera microcomputer in Embodiment 2.

FIGS. 9A and 9B are block diagrams showing connection of lens typedetermining devices provided in first and second interchangeable lenseswith a camera microcomputer in Embodiment 3 of the present invention.

FIGS. 10A and 10B show configurations of mounts and connectors, whichare provided in the camera and interchangeable lens of Embodiment 1.

FIGS. 11A and 11B are enlarged views of the connectors.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Exemplary embodiments of the present invention will hereinafter bedescribed with reference to the accompanying drawings.

Embodiment 1

FIG. 1A shows an interchangeable lens 100 as a lens unit and a camera 10as an image pickup apparatus to which the interchangeable lens 100 isdetachably (that is, interchangeably) attachable, which are Embodiment 1of the present invention and constitute a camera system. The camera 10and the interchangeable lens 100 each have a mount 1 that mechanicallycouples and electrically connects the camera 10 and the interchangeablelens 100. The mount includes electrical an electrical contacts forsupplying source power from the camera 10 to the interchangeable lens100 and for performing communication therebetween.

The camera 10 includes an image sensor (image pickup element) 11 thatphotoelectrically converts an object image as an optical image formed byan image taking lens 101 housed in the interchangeable lens 100 andoutputs an analog electrical signal. Moreover, the camera 10 includes anA/D converter 12 that converts the analog electrical signal output fromthe image sensor 11 into a digital signal and an image processor 13 thatperforms various image processes on the digital signal to produce animage signal. The image signal (still image or video) produced by theimage processor 13 is displayed on a display device 14 or recorded in arecording medium 15.

The camera 10 further includes a memory 16 that serves as a buffer forperforming the process on the image signal and stores operation programsto be used by a camera controller 18 described later. The camera 10 isadditionally provided with an operational input device 17 that includesa power switch for switching power on and off, an image capturing switchfor starting recording of the image signal and a selection/settingswitch for performing setting in various menus. The camera controller 18including a microcomputer controls the image processor 13 according tosignals from the operational input device 17 and controls communicationwith the interchangeable lens 100.

On the other hand, the interchangeable lens 100 includes a lens driver102 that drives actuators to move a focus lens, a zoom lens, an aperturestop and an image stabilizing lens included (but not shown) in the imagetaking lens 101. The interchangeable lens 100 is further provided with alens controller (lens side controller) 103 that includes a microcomputerand controls the lens driver 102 according to control signals from thecamera controller 18 through the communication.

FIG. 1B shows terminals provided in the mount for electrical connectionof the camera 10 (camera controller 18) and the interchangeable lens 100(lens controller 103).

An LCLK terminal (1-1) is a terminal for a communication clock signaloutput from the camera 10 to the interchangeable lens 100. A DCLterminal (1-2) is a terminal for communication data output from thecamera 10 to the interchangeable lens 100. A DLC terminal (1-3) is aterminal for communication data output from the interchangeable lens 100to the camera 10. The LCLK terminal, the DCL terminal and the DLCterminal each correspond to a seventh terminal and a seventh lens sideterminal.

An MIF terminal (1-4) is a terminal (sixth terminal and sixth lens sideterminal) for detecting attachment of the interchangeable lens 100 tothe camera 10. The microcomputer (hereinafter referred to as “a cameramicrocomputer”) 90 in the camera controller 18 detects that theinterchangeable lens 100 is attached to the camera 10 on a basis of avoltage of the MIF terminal.

A DTEF terminal (1-5) is a terminal (first terminal) for detecting typeof the interchangeable lens 100 attached to the camera 10. The cameramicrocomputer 90 detects (determines) the type of the interchangeablelens 100 attached to the camera 10 on a basis of a voltage of the DTEFterminal.

A VBAT terminal (1-6) is a terminal (fourth terminal and fourth lensside terminal) for supplying driving source power (VM) from the camera10 to the interchangeable lens 100; the driving source power is used forvarious operations of the interchangeable lens 100 such as drive ofvarious actuators, except communication control. A VDD terminal (1-7) isa terminal (second terminal) for supplying communication controllingsource power (VDD) from the camera 10 to the interchangeable lens 100;the communication controlling source power is used for communicationcontrol in the interchangeable lens 100. The VBAT terminal is providedseparately from the VDD terminal. This is because sharing of a sameterminal by the VBAT terminal and the VDD terminal may increaseelectrical current flowing through the terminal due to a heavy loadcaused by drive of the actuator or the like, which may affect operationof the microcomputer. A DGND terminal (1-8) is a terminal (thirdterminal and third lens side terminal) for connecting a communicationcontrol system of the camera 10 and interchangeable lens 100 to ground.That is, the DGND terminal is provided as a grounding terminal providedalong with the VDD terminal. A PGND terminal (1-9) is a terminal (fifthterminal and fifth lens side terminal) for connecting a mechanical drivesystem including the actuator such as a motor, which is provided in eachof the camera 10 and the interchangeable lens 100, to the ground. Inother words, the PGND terminal is provided as a grounding terminal alongwith the VBAT terminal.

Multiple types of interchangeable lenses are selectively attached to thecamera 10 of this embodiment; the interchangeable lenses performcommunication with the camera with different communication voltages fromone another. Description will hereinafter be made of a case where thetypes of the interchangeable lenses that are identified by the camera 10on the basis of the voltage of the DTEF terminal includes a firstinterchangeable lens and a second interchangeable lens whosecommunication voltage is different from that of the firstinterchangeable lens. The first interchangeable lens corresponds to afirst lens unit, and the second interchangeable lens corresponds to asecond lens unit. A detailed description of the communication voltagewill be made later.

In this embodiment, the first interchangeable lens uses 5V as itscommunication voltage, and the second interchangeable lens uses 3V asits communication voltage. The first interchangeable lens can switch itscommunication method between an open drain method with a relatively lowspeed of about tens of KHz and a CMOS communication method with arelatively high speed from hundreds of KHz to several MHz. Specifically,the first interchangeable lens performs an initial communication by theopen drain method in response to the attachment thereof to the camera,and then switches the communication method to the CMOS communicationmethod in response to establishment of the communication with the camerato perform high-speed communication therewith. On the other hand, thesecond interchangeable lens uses only the CMOS communication method. Alower communication voltage is more advantageous for increase ofcommunication speed.

A camera power supply 91 provided in the camera controller 18 converts abattery voltage supplied from a battery (not shown) included in thecamera 10 into voltages necessary for operations of respective circuitsin the camera 10. Specifically, the camera power supply 91 producesvoltages V1, V3 and VM.

First, description of the voltages that are output from the camera powersupply 91 shown in FIG. 1B will be made. A voltage of 5V as a firstvoltage (V1) is used as the communication voltage of the firstinterchangeable lens. The voltage of 5V is also used, as a fourthvoltage (VDD), as the communication controlling source power of thefirst and second interchangeable lenses. A voltage of 3V as a secondvoltage (V2) is used as the communication voltage of the secondinterchangeable lens, which is produced by a voltage converter 93 asdescribed in detail later. A voltage of 3.3V as a third voltage (V3) isused as an operation source voltage of the camera microcomputer 90. Avoltage of 4.8V as a fifth voltage (VM) is uses as the driving sourcevoltage of the actuators provided in the first and secondinterchangeable lenses. The first voltage V1 is different from thesecond voltage V2. On the other hand, the voltage V1 may be same as thevoltage V3 or VM, and the voltage V2 may be same as the voltage V3 orVM. In other words, it is only necessary that the third voltage V3 isdifferent from at least one of the first and second voltages V1 and V2(the third voltage V3 may be different from both the first and secondvoltages V1 and V2).

In response to turn-on of the above-mentioned power switch 92, thecamera microcomputer 90 starts supply of the VDD and VM from the camera10 to the interchangeable lens 100. In response to turn-off of the powerswitch 92, the camera microcomputer 90 ends the supply of the VDD and VMfrom the camera 10 to the interchangeable lens 100.

The camera microcomputer 90 performs communication with theinterchangeable lens 100 through the voltage converter 93. The cameramicrocomputer 90 has an LCLK_OUT terminal for outputting a communicationclock signal, a DCL_OUT terminal for sending communication data to theinterchangeable lens 100 and a DLC_IN terminal for receivingcommunication data from the interchangeable lens 100. The communicationclock signal and the communication data each correspond to a signal forcommunication. The camera microcomputer 90 serves as a cameracommunicating device.

Moreover, the camera microcomputer 90 has an MIF_IN terminal fordetecting the attachment of the interchangeable lens 100 to the camera10, a DTEF_IN terminal for identifying the type of the attachedinterchangeable lens 100 and a CNT_V_OUT terminal for outputting acommunication voltage switching signal to the voltage converter 93. Thecamera microcomputer 90 serves as a determiner. Operation of the voltageconverter 93 will be described below.

In addition, the camera microcomputer 90 further has a CNT_VDD_OUTterminal for outputting a current-applying signal to the power switch92, a connection terminal connected with the image processor 13 andanother connection terminal connected with the operational input device17.

A lens power supply 904 as a voltage producing device converts the VDD(5V) as the fourth voltage supplied from the camera 10 to theinterchangeable lens 100 through the second terminal (second lens sideterminal in the lens side mount) into a sixth voltage (V6). This sixthvoltage (V6) is, as described in detail below, one of the first andsecond voltages (V1 and V2) which corresponds to the type of theinterchangeable lens determined by the camera microcomputer 90. In FIG.1B, since the second interchangeable lens is attached, as theinterchangeable lens 100, to the camera 10, the sixth voltage is 3Vcorresponding to the second voltage (V2).

A microcomputer (hereinafter referred to as “a lens microcomputer”) 901provided in the lens controller 103 performs communicates with thecamera microcomputer 90 through the above-mentioned voltage converter93. The lens microcomputer 901 has an LCLK_IN terminal for receiving thecommunication clock signal, a DLC_OUT terminal for sending thecommunication data to the camera 10, a DCL_IN terminal for receiving thecommunication data from the camera 10 and a connection terminalconnected with the lens driver 102. The lens microcomputer 901 serves asa lens communicating device.

The camera microcomputer 90 further has an INT_IN terminal for receivingan interrupt signal from the interchangeable lens 100 and a CNT_EN_OUTterminal for outputting a switching signal to switch the communicationmethod with the interchangeable lens 100.

The lens microcomputer 901 further has an INT_OUT terminal foroutputting the interrupt signal to the camera 10. This interrupt signalis periodically and time-divisionally output and received in apredetermined communication period through the LCLK terminal (1-1) ofthe mount 1.

Next, description will be made of a configuration of a camera sideconnector including camera side contact pins constituting camera sideones of the above-described terminals provided in the mount 1 and a lensside connector including lens side contact patterns (accessory sidecontact surfaces) constituting lens side ones thereof in the mount 1.

FIG. 10A shows a camera side mount 201 viewed from a front side (objectside) in an optical axis direction corresponding to a direction in whichan optical axis of the image taking lens 101 extends. FIG. 11A is anenlarged view showing the camera side connector (constituted by a cameraside contact base 202 and the camera side contact pins 202 a ₁ to 202 a₉) provided in the camera side mount 201. FIG. 10B shows a lens sidemount 301 viewed from a rear side (image plane side) in the optical axisdirection. FIG. 11B is an enlarged view showing the lens side connector(constituted by a lens side contact base 302 and the lens side contactpatterns 302 a ₁ to 302 a ₉) provided in the lens side mount 301.

The camera side mount 201 is fixed at a front end portion of a camerabody (not shown) as a chassis. The camera side mount 201 has, at itsouter circumference side front end, a ring-shaped mount base surface 201b provided for securing a predetermined flange back, and also has,further inside than the mount base surface 201 b at three places in itscircumferential direction (hereinafter referred to as “a mountcircumferential direction”), camera side bayonet claws 201 a. Moreover,the camera side mount 201 is provided with a lock pin 205 forpositioning of the camera side mount 201 and the lens side mount 301 intheir relative rotational direction; the lock pin 205 is movable so asto protrude and retract with respect to the mount base surface 201 b.The lens side mount (accessory side mount) 301 is fixed to a rear endportion (not shown) of the interchangeable lens. The lens side mount 301has, at its outer circumferential side rear end portion, a mount basesurface 301 b that is a reference surface in the optical axis direction,and has, further inside than the mount base surface 301 b at threeplaces in its circumferential direction (mount circumferentialdirection), lens side (accessory side) bayonet claws 301 a. Moreover,the lens side mount 301 is provided with a lock hole portion 301 c intowhich the lock pin 205 provided in the camera side mount 201 can beinserted; the lock hole portion 301 c is formed so as to open at themount base surface 301 b. The lock hole portion 301 c has, in the mountcircumferential direction (that is, a relative rotation direction of thecamera side and lens side mounts 201 and 301), an inner diameter thatcan engage with the lock pin 205 with almost no backlash, and has, in aradial direction (hereinafter referred to as “a mount radial direction”)of the lens side mount 301, a longitudinal hole shape with an innerdiameter larger than an outer diameter of the lock pin 205 to somedegree. The longitudinal hole shape is provided in order to enablesmooth insertion of the lock pin 205 into the lock hole portion 301 cwhen the interchangeable lens 100 is attached to (relatively rotatedwith respect to) the camera 10.

In a partial area further inside than the bayonet claws 201 a of thecamera side mount 201, a camera side contact base (camera side contactholding portion) 202 that holds nine camera side contact pins 202 a ₁,202 a ₂, . . . , 202 a ₉ arranged in the mount circumferential directionis formed. The camera side contact pins 202 a ₁ to 202 a ₉ are insertedinto pin holding hole portions formed in the camera side contact base202 so as to independently protrude forward and retract rearward (thatis, so as to be independently movable in protruding and retractingdirections). At bottoms of the pin holding hole portions, a flexibleprinted wiring board 206 is disposed. Moreover, a contact spring (202 b₁, 202 b ₂, . . . , 202 b ₉) is disposed between the flexible printedwiring board 206 and a flange portion of each camera side contact pin(202 a ₁, 202 a ₂, . . . , 202 a ₉); the contact spring biases thecamera side contact pin so as to protrude it forward from the cameraside contact base 202.

The camera side contact pins 202 a ₁ to 202 a ₉ are, in this order,connected with the DTEF terminal, the DGND terminal, the LCLK terminal,the DLC terminal, the DCL terminal, the PGND terminal, the VBATterminal, the VDD terminal and the MIF terminal, described in FIG. 1B.The camera side contact pin 202 a ₂ corresponds to a fifth camera sidecontact pin, the camera side contact pins 202 a ₄ and 202 a ₅ eachcorrespond to an eighth camera side contact pin, the camera side contactpin 202 a ₅ corresponds to a seventh camera side contact pin and thecamera side contact pin 202 a ₈ correspond to a fourth camera sidecontact pin.

The camera side contact base 202, the camera side contact pins 202 a_(n) (n=1 to 9 and the same applies to the following description) andthe contact springs 202 b _(n) and the flexible printed wiring board 206constitute the camera side connector.

In a partial area further inside than the bayonet claws 301 a of thelens side mount 301, a lens side contact base (lens side contact holdingportion) 302 that holds nine rectangular lens side contact patterns 302a ₁, 302 a ₂, . . . , 302 a ₉ arranged in the mount circumferentialdirection is formed. The lens side contact pattern may have anothershape than a rectangular shape, such as a circular shape.

The lens side contact patterns 302 a ₁ to 302 a ₉ are connected with thelens controller 103 shown in FIG. 1B via a flexible printed wiring board306. In portions of the lens side contact base 302 adjacent to patternholding portions that respectively hold the lens side contact patterns302 a ₁ to 302 a ₉, recessed (concave) portions 302 z that recessforward further than the pattern holding portions. Moreover, a slope 302w is formed between each pattern holding portion and each recessedportion 302 z adjacent thereto. In the following description, thepattern holding portions in the lens side contact base 302 and the lensside contact patterns 302 a ₁ to 302 a ₉ are collectively referred to as“the lens side contact base 302”.

The lens side contact patterns 302 a ₁ to 302 a ₉ correspond, in thisorder, to the camera side contact pins 202 a ₁ to 202 a ₉ connected withthe DTEF terminal, the DGND terminal, the LCLK terminal, the DLCterminal, the DCL terminal, the PGND terminal, the VBAT terminal, theVDD terminal and the MIF terminal. The lens side contact pattern 302 a ₂corresponds to a fifth accessory side contact surface, the lens sidecontact patterns 302 a ₄ and 302 a ₅ each correspond to an eighthaccessory side contact surface, the lens side contact pattern 302 a ₅corresponds to a seventh accessory side contact surface and the lensside contact pattern 302 a ₈ correspond to a fourth accessory sidecontact surface.

The lens side contact base 302 (including the recessed portion 302 z andthe slope 302 w), the lens side contact patterns 302 a _(n) (n=1 to 9and the same applies to the following description) and the flexibleprinted wiring board 306 constitute the lens side connector.

The camera side contact pin 202 a _(n) and the lens side contact pattern302 a _(n) are arranged at positions at which they make a pair with eachother (that is, positions at which they make contact with each other) inthe coupling completion state of the camera 10 and the interchangeablelens 100. At a time of the lens attachment, the lens side contact base302 (including the lens side contact pattern 302 a _(n) as mentionedabove) coming in contact with the camera side contact pin 202 a _(n)pushes this camera side contact pin 202 a _(n) into the camera sidecontact base 202 with charging the contact spring 202 b _(n). As aresult, the camera side contact pin 202 a _(n) makes contact with thecorresponding (paired) lens side contact pattern 302 a _(n) withpressure, and thereby electrical connection between the camera 10 andthe interchangeable lens 100 is established.

Description will be made of the detection of the attachment of theinterchangeable lens (first and second interchangeable lenses) 100 tothe camera 10. The MIF_IN terminal of the camera microcomputer 90 ispulled up to the source voltage by a resistance R2 (for example, 100KΩ)provided in the camera controller 18 and thereby becomes H (High) whenthe interchangeable lens 100 is not attached to the camera 10. On theother hand, the MIF_IN terminal is connected with the ground (GND) inthe interchangeable lens 100 when the interchangeable lens (first andsecond interchangeable lenses) 100 is attached to the camera 10, andthereby becomes L (low) at a point of time when the attachment of theinterchangeable lens 100 is made, irrespective of the type of theattached interchangeable lens 100.

Description will be made of an exemplary configuration of the lens typedetermining device 903 provided in the lens controller 103 withreference to FIGS. 2A and 2B. The lens type determining device 903 isconstituted by a resistance RL as a second resistance provided betweenthe DTEF terminal in the mount 1 and the GND. A resistance value of theresistance RL is preset to a predetermined value corresponding(assigned) to the type of the interchangeable lens. For example, theresistance value of the resistance RL provided in the firstinterchangeable lens shown in FIG. 2A is set to 0Ω, and that of theresistance RL provided in the second interchangeable lens shown in FIG.2B is set to 300KΩ.

In the camera 10, a resistance R1 (for example, 100KΩ) as a firstresistance is connected between the DTEF terminal in the mount 1 (inother words, a first lens side terminal provided in a lens side mount)and the voltage (V3) of the operating source power for the cameramicrocomputer 90 to pull up the DTEF terminal to that operating sourcevoltage (V3). The DTEF terminal is connected with the DTEF_IN terminalof the camera microcomputer 90. The DTEF_IN terminal of the cameramicrocomputer 90 is provided with an AD conversion function (10 Bit ADconversion function in this embodiment).

Description will be made of a lens type determination operation(hereinafter also referred to as “lens type determination”) of thecamera microcomputer 90 for determining the type of the interchangeablelens 100 attached to the camera 10. The camera microcomputer 90 performsthe lens type determination on the basis of the voltage value input tothe DTEF_IN terminal. Specifically, the camera microcomputer 90 performsAD conversion of the input voltage value and performs the lens typedetermination by comparing the AD converted value with lens typedetermination references stored in the camera microcomputer 90.

For example, when the first interchangeable lens is attached to thecamera 10, the AD converted value of the voltage value input to theDTEF_IN terminal is decided, by a resistance ratio RL/(R1+RL) where R1is 100KΩ and RL is 0Ω, as approximately “0x0000”. The cameramicrocomputer 90 detects that the AD converted value obtained from theDTEF_IN terminal is within a range of “0x0000 to 0x007F”, which is afirst lens type determination reference, and thereby determines that theattached interchangeable lens is the first interchangeable lens.

On the other hand, when the second interchangeable lens is attached tothe camera 10, the AD converted value of the voltage value input to theDTEF_IN terminal is decided, by the resistance ratio RL/(R1+RL) where R1is 100KΩ and RL is 300Ω, as approximately “0x02FF”. The cameramicrocomputer 90 detects that the AD converted value obtained from theDTEF_IN terminal is within a range of “0x0280 to 0x037F”, which is asecond lens type determination reference, and thereby determines thatthe attached interchangeable lens is the second interchangeable lens.

Although the above description was made of the case where the resistancevalue of the resistance RL of the first interchangeable lens is 0Ω byusing a 0Ω resistance, a configuration may be employed which connectsthe DTEF terminal with the GND in the first interchangeable lens.Moreover, the value of the resistance RL may be produced by using alinear region of a switching element such as a transistor or by using asubstrate pattern.

Next, description will be made of a voltage switching operation of thevoltage converter 93 in the camera controller 18 with reference to FIG.3. In FIG. 3, an FET1 is a PchFET whose source terminal is connectedwith 5V output from the camera power source 91, whose gate terminal isconnected with the CNT_V_OUT terminal and whose drain terminal iswired-connected with an output terminal of an REG1 described later.

The REG1 is a series regulator that outputs 3V, whose input (IN)terminal is connected with 5V and whose output (OUT) terminal has areverse voltage resistance of about 5V and is wired-connected with thedrain terminal of the FET1. An output of wired-OR of an output from theFET1 and an output from the REG1 is used as a voltage V_(s). An ENterminal (which becomes active by input of H) is connected with theCNT_V_OUT terminal. In other words, when the CNT_V_OUT terminal is L,the FET1 is turned on, the REG1 is turned off and thereby the V_(s)becomes 5V. On the other hand, when the CNT_V_OUT terminal is H, theFET1 is turned off, the REG1 is turned on and thereby the V_(s) becomes3V. The FET1 and REG1 constitute a voltage selecting device.

Description will be made of an LCLK line. An IC1 and an IC2 are each athree state buffer. The IC1 is a TTL-level input buffer. A power sourceterminal of the IC1 is connected with 5V, and an input terminal thereofis connected with the LCLK_OUT terminal of the camera microcomputer 90.Moreover, an EN terminal of the IC1 is connected with the CNT_EN_OUTterminal of the camera microcomputer 90, and an output terminal thereofis connected with an input terminal of the IC2. The IC1 corresponds to afirst voltage converter.

The IC2 is a CMOS-level input buffer and is provided with an inputtolerant function allowing an input voltage up to about 5.5V. A powersupply terminal of the IC2 is connected with the V_(s), and the inputterminal thereof is connected with the output terminal of the IC1.Moreover, an EN terminal of the IC2 is connected with the terminalCNT_EN_OUT of the camera microcomputer 90, and an output terminalthereof is connected with the LCLK terminal of the camera side mount.The IC2 corresponds to a second voltage converter.

The communication clock signal output by the camera microcomputer 90 isdecided depending on the operation source voltage of the cameramicrocomputer 90, and thereby has an amplitude of 3.3V. The IC1 as theTTL level input buffer detects 3.3V as an H input and outputs, to theIC2, a voltage with an amplitude of 5V corresponding to the sourcevoltage of the IC1. The IC2 detects 5V as an H input, outputs a voltagewith an amplitude of 5V when the V_(s) is 5V, and outputs a voltage withan amplitude of 3V when the V_(s) is 3V. The IC2 can receive the 5Voutput from the IC1 by its input tolerant function. Thus, switching ofthe V_(s) changes the output voltage of the communication clock signal.

In addition, an IC6, an IC7 and an FET2 are connected in parallel withthe LCLK line. The IC6 is a three state buffer. The IC6 is a CMOS levelinput buffer and is provided with an input tolerant function allowing aninput voltage up to about 5.5V. An input terminal of the IC6 isconnected with the above-mentioned interrupt signal from the lensmicrocomputer 901, and an output terminal thereof is connected with theINT_IN terminal of the camera microcomputer 90. The IC6 converts theinterrupt signal from the lens microcomputer 901 into 3.3 V that is theoperation source voltage of the camera microcomputer 90 to output it tothe INT_IN terminal of the camera microcomputer 90.

The IC7 has a NOR logic gate. An input-A terminal of the IC 7 isconnected with the communication clock signal, and an input-B terminalthereof is connected with the CNT_EN_OUT terminal. When the CNT_EN_OUTterminal is L and the LCLK_OUT terminal is also L, the FET2 is turnedon, and thereby the LCLK terminal (1-1) becomes L.

The FET2 is a PchFET and is used for the open drain communication whenthe first interchangeable lens is attached to the camera 10. When theCNT_EN_OUT terminal is H, the IC1 and IC2 become active and the IC6 andIC7 become inactive (HiZ), thereby enabling the CMOS communication. Onthe other hand, when the CNT_EN_OUT terminal is L, the IC1 and IC2become inactive (HiZ) and the IC6 and IC7 become active, therebyenabling the open drain communication. Such operation makes it possibleto input the interrupt signal output by the lens microcomputer 901 tothe camera microcomputer 90 in the communication period allowing theinput/output of the interrupt signal.

Next, description will be made of a DCL line. An IC3 and an IC4 are eacha three state buffer. The IC3 is a TTL level input buffer. A powersupply terminal of the IC3 is connected with 5V, and an input terminalthereof is connected with the DCL_OUT terminal of the cameramicrocomputer 90. Moreover, an EN terminal of the IC3 is connected withthe CNT_EN_OUT terminal, and an output terminal thereof is connectedwith an input terminal of the IC4. The IC3 corresponds to a firstvoltage converter.

The IC4 is a CMOS level input buffer and is provided with an inputtolerant function allowing an input voltage up to about 5.5V. A powersource terminal of the IC4 is connected with the V_(s), and an inputterminal thereof is connected with the output terminal of the IC3.Moreover, an EN terminal of the IC4 is connected with the CNT_EN_OUTterminal, and an output terminal thereof is connected with the DCLterminal of the lens side mount. The IC4 corresponds to a second voltageconverter.

The communication data output by the camera microcomputer 90 is decideddepending on the operation source voltage of the camera microcomputer90, and thereby has an amplitude of 3.3V. The IC3 as the TTL level inputbuffer detects 3.3V as an H input and outputs, to the IC4, a voltagewith an amplitude of 5V corresponding to the source voltage of the IC3.The IC4 detects 5V as an H input, outputs a voltage with an amplitude of5V when the V_(s) is 5V, and outputs a voltage with an amplitude of 3Vwhen the V_(s) is 3V. The IC4 can receive the 5V output from the IC3 byits input tolerant function. Thus, switching of the V_(s) changes theoutput voltage of the communication data.

In addition, an IC8 and an FET3 are connected in parallel with the DCLline. The IC8 has a NOR logic gate. An input-A terminal of the IC 8 isconnected with the DCL_OUT terminal, and an input-B terminal thereof isconnected with the CNT_EN_OUT terminal. Thus, when the CNT_EN_OUTterminal is L and the DCL_OUT terminal is also L, the FET3 is turned on,and thereby the DCL terminal (1-2) becomes L.

The FET3 is a PchFET and is used for the open drain communication whenthe first interchangeable lens is attached to the camera 10. When theCNT_EN_OUT terminal is H, the IC3 and IC4 become active and the IC8becomes inactive (HiZ), thereby enabling the CMOS communication. On theother hand, when the CNT_EN_OUT terminal is L, the IC3 and IC4 becomeinactive (HiZ) and the IC8 becomes active, thereby enabling the opendrain communication.

An IC5 is connected in series with the DLC line. The IC5 is a buffer.The IC5 is a CMOS level input buffer and is provided with an inputtolerant function allowing an input voltage up to about 5.5V. A powersource terminal of the IC5 is connected with the 3.3V, and an inputterminal thereof is connected with the DLC terminal of the lens sidemount. Moreover, an output terminal of the IC5 is connected with theDLC_IN terminal of the camera microcomputer 90.

The DLC_OUT terminal of the lens microcomputer 901 in the firstinterchangeable lens outputs a voltage with an amplitude of 5V, and onthe other hand the DLC_OUT terminal of the lens microcomputer 901 in thesecond interchangeable lens outputs a voltage with an amplitude of 3V.However, when any of these interchangeable lenses is attached to thecamera 10, the IC5 converts the above voltage output from the DLC_OUTterminal of the lens microcomputer 901 into a voltage with an amplitudeof 3.3V and then inputs it to the DLC_IN terminal of the cameramicrocomputer 90.

The camera microcomputer 90 controls the CNT_V_OUT terminal according toa logic table shown in Table 1.

TABLE 1 FIRST SECOND NON-COMPLIANT LENS ATTACHED INTERCHANGEABLE LENSRESERVED LENS DTEF_IN 0x0000~0x007F 0x0280~0x037F 0x0080~0x027F0x0380~0x03FF CNT_V_OUT H L — — COMMUNICATION 5 V 3 V — — VOLTAGECNT_EN_OUT H L H — — COMMUNICATION CMOS OPEN CMOS NO COMMUNICATIONMETHOD DRAIN

As described above, the camera microcomputer 90 determines the type ofthe attached interchangeable lens 100 on the basis of the voltage value(AD converted value) input to the DTEF_IN terminal. Then, the cameramicrocomputer 90 controls a logic signal output from the CNT_V_OUTterminal depending on a result of the lens type determination of theattached interchangeable lens 100. Specifically, when determining fromthe voltage value of the DTEF_IN terminal that the attachedinterchangeable lens 100 is the first interchangeable lens, the cameramicrocomputer 90 outputs H from the CNT_V_OUT terminal to control thecommunication voltage to the V1. On the other hand, when determiningfrom the voltage value of the DTEF_IN terminal that the attachedinterchangeable lens 100 is the second interchangeable lens, the cameramicrocomputer 90 outputs L from the CNT_V_OUT terminal to control thecommunication voltage to the V2.

Moreover, when detecting, as the voltage value (AD converted value) ofthe DTEF_IN terminal, a voltage out of the range of the above-mentionedfirst and second lens type determination references, the cameramicrocomputer 90 determines that the attached interchangeable lens is “anon-compliant lens” to which the camera 10 is not compliant or reservesthe determination because of being unable to make a normal lens typedetermination. In these cases, the camera microcomputer 90 does notperform communication with the attached interchangeable lens 100.

A flowchart of FIG. 4 shows a communication setting operation performedby the camera microcomputer 90. The camera microcomputer 90 executesthis operation according to a computer program stored in the memory 16.

At step S60, the camera microcomputer 90 reads the voltage value (H orL) from the MIF_IN terminal. Next, at step S61, the camera microcomputer90 reads the voltage value from the DTEF_IN terminal. These steps S60and S61 may be performed in this order, and may be performedsimultaneously.

Next, at step S62, the camera microcomputer 90 determines the type ofthe interchangeable lens 100 attached to the camera 10 on the basis ofthe voltage value of the DTEF_IN terminal as described above. Ifdetermining that the attached interchangeable lens 100 is the firstinterchangeable lens (lens type 1), the camera microcomputer 90 outputsH from the CNT_V_OUT terminal to set the communication voltage V1 atstep S63, and then proceeds to step S63A. On the other hand, ifdetermining that the attached interchangeable lens 100 is the secondinterchangeable lens (lens type 2), the camera microcomputer 90 outputsL from the CNT_V_OUT terminal to set the communication voltage V2 atstep S64, and then proceeds to step S64A. If determining that theattached interchangeable lens 100 is neither the first nor secondinterchangeable lens, the camera microcomputer 90 determines that theattached interchangeable lens 100 is “the non-compliant lens” orreserves the determination at step S65, and then proceeds to step S65A.

At steps S63A and S64A, the camera microcomputer 90 starts thecommunication with the attached interchangeable lens 100 with the setcommunication voltage. At step S65A, the camera microcomputer 90 doesnot start the communication with the attached interchangeable lens 100,but performs a warning process for informing a user.

Thereafter, at step S66, the camera microcomputer 90 determines whetheror not a power-off interruption due to an off operation of the powerswitch 62 has been input. If the power-off interruption has been input,the camera microcomputer 90 performs a power-off process at step S67. Onthe other hand, if the power-off interruption has not been input, thecamera microcomputer 90 proceeds to step S68 to determine whether or notH has been input from the MIF_IN terminal, that is, whether or not theinterchangeable lens 100 has been detached from the camera 10. If H hasbeen input from the MIF_IN terminal, the camera microcomputer 90proceeds to step S69 to stop the communication with the interchangeablelens 100, and then returns to step S60. On the other hand, If H has notbeen input from the MIF_IN terminal, the camera microcomputer 90 returnsto step S66.

FIGS. 5A and 5B show exemplary input and output timings of the MIF_INterminal, the DTEF_IN terminal, the CNT_V_OUT terminal, the CNT_VDD_OUTterminal of the camera microcomputer 90 and the LCLK terminal of themount 1. FIG. 5A shows the input and output timings when the firstinterchangeable lens is attached to the camera 10, and FIG. 5B shows theinput and output timings when the second interchangeable lens isattached to the camera 10. In these figures, t0 represents a time atwhich voltage input to the DTEF_IN terminal is made during a process ofattachment of the interchangeable lens 100 to the camera 10 (hereinafterreferred to as “a lens attachment process”), and t1 represents a time atwhich voltage input to the MIF_IN terminal is made during the lensattachment process. Moreover, t2 represents a time at which the camera10 is activated (power is turned on), t3 represents a time at which thelens type determination and the communication voltage setting are made,and t4 represents a time at which the power supply to the attachedinterchangeable lens 100 and the communication therewith are started.

Although FIGS. 5A and 5B show the case where the time t0 is identical tothe time t1, the time t1 may be later than the time t0. When a time atwhich contacts for the DTEF terminal in the mount 1 (camera side andlens side mounts) make contact is earlier than a time at which contactsfor the MIF terminal make contact, the time t0 is earlier than the timet1. When these times at which the contacts make contact are identical toeach other, the time t0 is identical to the time t1.

When any of the first and second interchangeable lenses is attached tothe camera 10, the voltage input to the MIF_IN terminal is made (t1)simultaneously with (or after) the voltage input to the DTEF_IN terminalis made (t0). Then, after the camera is activated (t2), the lens typedetermination and the communication voltage setting depending on theresult of the lens type determination are made (t3), and thereafter thepower supply to the interchangeable lens 100 and the communicationtherewith are started (t4). In a case where the interchangeable lens isattached to the camera 10 after the camera 10 is activated, though theorder of the times t1, t0 and t2 is reversed, the voltage input to theMIF_IN terminal is made simultaneously with (or after) the voltage inputto the DTEF_IN terminal is made.

Although this embodiment described the case where the voltage V1 is 5V,the voltage V2 is 3V, the voltage V3 is 3.3V and the voltage VM is 4.8V,these voltages are merely examples, and the voltages V1, V2, V3 and VMmay be set to other voltages. Although the voltage V1 is different fromthe voltage V2, the voltage V1 may be same as the voltage V3 or VM, andthe voltage V2 may be same as V3 or VM. In other word, it is onlynecessary that the voltage V3 is different from at least one of thevoltages V1 and V2. Moreover, although this embodiment described thecase of using the buffer as the voltage converter converting (changing)the communication voltage, the voltage converter is not limited thereto,and other communication voltage conversion methods may be employed. Forexample, the communication voltage conversion may be performed bysetting the communication method to the open drain method and switchingthe source voltage for signal pull-up.

In addition, although this embodiment described, as the method forproducing the voltage of the DTEF terminal corresponding to the lenstype, the resistance voltage division using the resistances R1 and RL,other methods may be employed. For example, a method may be employedwhich provides, to the interchangeable lens, a reference power sourcecircuit (device) constituted by a DC-DC converter, a series regulator, adiode or the like. Specifically, a case of providing the seriesregulator in the second interchangeable lens is as follows. In thiscase, an input voltage of the series regulator is set to the fourthvoltage (VDD) supplied from the camera 10 to the interchangeable lens100. Moreover, an output voltage of the series regulator (that is, apredetermined voltage output to the first lens side terminal) is set toa voltage at which the AD converted value of the DTEF terminal fallswithin the range of the second lens type determination reference “0x0280to 0x037F”, that is, to a voltage assigned to the second interchangeablelens. Therefore, the camera microcomputer 90 detecting that the ADconverted value of the DTEF terminal is within the range of the secondlens type determination reference “0x0280-0x037F” can determine that theattached interchangeable lens is the second interchangeable lens.

Embodiment 2

Next, description will be made of a second embodiment (Embodiment 2) ofthe present invention with reference to FIGS. 6, 7, 8A and 8B. A basicconfiguration of a camera system including a camera and aninterchangeable lens, which are Embodiment 2, is same as that shown inFIG. 1A in Embodiment 1. In this embodiment, the camera and theinterchangeable lens are also denoted by reference numerals 10 and 100,respectively. However, as shown in FIG. 6, a camera microcomputer 20 anda lens microcomputer 221 of a second interchangeable lens in thisembodiment are not provided with the INT_IN and INT_OUT terminalsprovided in the camera microcomputer 90 and the lens microcomputer 901in Embodiment 1 for inputting the interrupt signal from the lensmicrocomputer 901 to the camera microcomputer 90. Moreover, the cameramicrocomputer 20 in this embodiment is not provided with the CNT_EN_OUTterminal provided in the camera microcomputer 90 in Embodiment 1 foroutputting the switching signal to switch the communication method withthe interchangeable lens. Elements and terminals in a camera controller18, the camera microcomputer 20, a lens controller 103 and the lensmicrocomputer 221 in this embodiment common to those in Embodiment 1 aredenoted by same reference numerals and characters as those in Embodiment1.

A camera power supply 21 provided in the camera controller 18 converts abattery voltage supplied from a battery (not shown) included in thecamera 10 into voltages necessary for operations of respective circuitsin the camera 10. Specifically, the camera power supply 21 producesvoltages V1, V2, V3 and VM.

The voltage (first voltage) V1 is a voltage as communication controllingsource power (VDD) of the interchangeable lens (first and secondinterchangeable lenses) 100 and a communication voltage of the firstinterchangeable lens. The voltage (second voltage) V2 is a communicationvoltage of the second interchangeable lens. The voltage (third voltage)V3 is a voltage as operating source power of the camera microcomputer20. The voltage VM is a voltage as driving source power of actuatorsprovided in the first and second interchangeable lenses. Although thevoltage V1 is different from the voltage V2, the voltage V1 may be sameas the voltage V3 or VM, and the voltage V2 may be same as the voltageV3 or VM (or may be different from both the voltages V3 and VM).

In response to turn-on of the power switch 22, the camera microcomputer20 starts supply of the VDD and VM from the camera 10 to theinterchangeable lens 100. In response to turn-off of the power switch22, the camera microcomputer 20 ends the supply of the VDD and VM fromthe camera 10 to the interchangeable lens 100.

FIG. 7 shows an exemplary configuration of a voltage converter 23. Avoltage selector 51 has a function of outputting, to an OUT terminal,any one of two voltages input to a VIN1 terminal and a VIN2 terminalaccording to a logic signal at an SEL terminal. Specifically, thevoltage selector 51 outputs the voltage input to the VIN1 terminal whenthe input to the SEL terminal is L, and the voltage selector 51 outputsthe voltage input to the VIN2 terminal when the input to the SELterminal is H. The voltage V1 is connected to the VIN1 terminal, thevoltage V2 is connected to the VIN2 terminal, and the CNT_V_OUT terminalof the camera microcomputer 20 is connected to the SEL terminal. Theoutput of the OUT terminal is hereinafter referred to as “Vs”.

Level shifters 52, 53 and 54 each have a function of converting avoltage of a signal input to an SIN terminal from a voltage of a VINterminal into a voltage of a VOUT (VO in the figure) terminal and thenoutputting the converted voltage from an SOUT terminal.

In the level shifter 52, the SIN terminal is connected with the LCLK_OUTterminal of the camera microcomputer 20, and the SOUT terminal isconnected with the LCLK terminal of the mount 1 of the camera 10 and theinterchangeable lens 100. Moreover, the VIN terminal is connected withthe V3 that is the same voltage as the operating source power voltage ofthe camera microcomputer 20, and the VOUT terminal is connected with theV_(s) output from the voltage selector 51. In the level shifter 53, theSIN terminal is connected with the DCL_OUT terminal of the cameramicrocomputer 20, and the SOUT terminal is connected with the DCLterminal of the mount 1. Moreover, the VIN terminal is connected withthe V3 that is the same voltage as the operating source power voltage ofthe camera microcomputer 20, and the VOUT terminal is connected with theV_(s) output from the voltage selector 51. In the level shifter 54, theSIN terminal is connected with the DLC terminal of the mount 1, and theSOUT terminal is connected with the DLC_IN terminal of the cameramicrocomputer 20. Moreover, the VIN terminal is connected with the V_(s)output from the voltage selector 51, and the VOUT terminal is connectedwith the V3 that is the same voltage as the operating source powervoltage of the camera microcomputer 20. Thus, the V_(S) (that is, V1 orV2) output from the voltage selector 51 is used as the communicationvoltage between the camera 10 and the interchangeable lens 100.

Description will be made of a voltage switching operation of the voltageconverter 23. The camera microcomputer 20 controls the CNT_V_OUTterminal according to a logic table shown in Table 2.

TABLE 2 FIRST SECOND NON-COMPLIANT LENS ATTACHED INTERCHANGEABLE LENSRESERVED LENS DTEF_IN 0x0000~0x007F 0x0280~0x037F 0x0080~0x027F0x0380~0x03FF CNT_V_OUT H L — — COMMUNICATION V1 V2 NO COMMUNICATIONVOLTAGE

As well as the camera microcomputer 90 in Embodiment 1, the cameramicrocomputer 20 determines the type of the attached interchangeablelens 100 on the basis of the voltage value (AD converted value) input tothe DTEF_IN terminal. Then, the camera microcomputer 20 controls a logicsignal output from the CNT_V_OUT terminal depending on a result of thelens type determination of the attached interchangeable lens 100.Specifically, when determining from the voltage value of the DTEF_INterminal that the attached interchangeable lens 100 is the firstinterchangeable lens, the camera microcomputer 20 outputs H from theCNT_V_OUT terminal to control the communication voltage to the V1. Onthe other hand, when determining from the voltage value of the DTEF_INterminal that the attached interchangeable lens 100 is the secondinterchangeable lens, the camera microcomputer 20 outputs L from theCNT_V_OUT terminal to control the communication voltage to the V2.

Moreover, when detecting, as the voltage value (AD converted value) ofthe DTEF_IN terminal, a voltage out of ranges of first and second lenstype determination references, the camera microcomputer 20 determinesthat the attached interchangeable lens is “a non-compliant lens” towhich the camera 10 is not compliant or reserves the determinationbecause of being unable to make a normal lens type determination. Inthese cases, the camera microcomputer 20 does not perform communicationwith the attached interchangeable lens 100.

FIGS. 8A and 8B show exemplary input and output timings of the MIF_INterminal, the DTEF_IN terminal, the CNT_V_OUT terminal, the CNT_VDD_OUTterminal of the camera microcomputer 20 and the LCLK terminal of themount 1. FIG. 8A shows the input and output timings when the firstinterchangeable lens is attached to the camera 10, and FIG. 8B shows theinput and output timings when the second interchangeable lens isattached to the camera 10. In these figures, t0 represents a time atwhich voltage input to the DTEF_IN terminal is made during a lensattachment process, and t1 represents a time at which voltage input tothe MIF_IN terminal is made during the lens attachment process.Moreover, t2 represents a time at which the camera 10 is activated(power is turned on), t3 represents a time at which the lens typedetermination and the communication voltage setting are made, and t4represents a time at which the power supply to the attachedinterchangeable lens 100 and the communication therewith are started.Although FIGS. 8A and 8B show the case where the time t0 is earlier thanthe time t1, the time t1 may be identical to the time t0. When a time atwhich contacts for the DTEF terminal in the mount 1 (camera side andlens side mounts) make contact is earlier than a time at which contactsfor the MIF terminal make contact, the time t0 is earlier than the timet1. When these times at which the contacts make contact are identical toeach other, the time t0 is identical to the time t1. In addition,although the times at which the voltage input to the DTEF_IN terminaland the voltage input to the MIF_IN terminal are made are respectively,as described above, t0 and t1, the camera microcomputer 20 reads thevoltage value of the DTEF_IN terminal after the MIF_IN terminal becomesL.

In both the cases where the first interchangeable lens is attached tothe camera 10 and where the second interchangeable lens is attachedthereto, the voltage input to the MIF_IN terminal is made (t1) after (orsimultaneously with) the voltage input to the DTEF_IN terminal (t0).Then, after the camera 10 is activated (t2), the lens type determinationand the communication voltage setting depending on the result of thelens type determination are performed (t3). Thereafter, the power supplyto the interchangeable lens 100 and the communication therewith arestarted (t4). When the interchangeable lens is attached to the camera 10after the camera 10 is activated, though the time t2 is before the timest0 and t1, the voltage input to the MIF_IN terminal is performed after(or simultaneously with) the voltage input to the DTEF_IN terminal.

Embodiment 3

FIGS. 9A and 9B show an exemplary configuration of a lens typedetermining device provided in an interchangeable lens (first and secondinterchangeable lenses) that is a third embodiment (Embodiment 3) of thepresent invention. The lens type determining device is connected,through the DTEF terminal in the mount, with the DTEF_IN terminal of thecamera microcomputer 20 shown in Embodiment 2. In the firstinterchangeable lens shown in FIG. 9A, the lens type determining deviceis directly connected with ground of the first interchangeable lens,without providing the 0Ω resistance RL shown in Embodiment 1 (FIG. 2A).In this case, the camera microcomputer 20 detects L through the DTEF_INterminal. On the other hand, in the second interchangeable lens shown inFIG. 9B, the lens type determining device merely opens the DTEFterminal. In this case, the camera microcomputer 20 detects H throughthe DTEF_IN terminal because the DTEF_IN terminal is pulled up to thesource voltage (V3) by a resistance R1 (for example, 100KΩ) as a firstresistance.

Thus, the type of the interchangeable lens can be determined evenwithout using the resistance ratio described in Embodiment 1.

According to each of the above-described embodiments, the camera towhich the plurality of the interchangeable lenses (lens units) whosecommunication voltages are different from one another areinterchangeably attached switches the communication voltage depending onthe type of the attached interchangeable lens, without changing thesource voltage to be supplied to the respective interchangeable lenses.Thereby, necessity of providing, to the camera, multiple power sourcesfor supplying different powers to the respective interchangeable lensescan be eliminated. Moreover, even when the camera erroneously determinesthe type of the attached interchangeable lens, supply of a sourcevoltage or current exceeding a rated one to the interchangeable lens canbe prevented.

Furthermore, the present invention is not limited to these embodimentsand various variations and modifications may be made without departingfrom the scope of the present invention.

This application claims the benefit of Japanese Patent Application Nos.2013-049118, filed on Mar. 12, 2013, 2012-085426, 2012-085190 and2012-085223 filed on Apr. 4, 2012 which are hereby incorporated byreference herein in their entirety.

What is claimed is:
 1. A lens unit comprising: a mount to mechanicallycouple with an image pickup apparatus and to electrically connect thelens unit with the image pickup apparatus; and a lens controllerconfigured to receive power supply at a fourth voltage from the imagepickup apparatus, to produce from the fourth voltage a sixth voltagedifferent from the fourth voltage, and to perform the communication withthe image pickup apparatus with the sixth voltage, wherein the mountincludes a first lens terminal enabling provision of a type of the lensunit by a configuration to output a predetermined voltage correspondingto the type of the lens unit in a state of being attached to the imagepickup apparatus.
 2. A lens unit according to claim 1, wherein the firstlens terminal is connected with an element having a resistance valuecorresponding to the type of the lens unit.
 3. A lens unit according toclaim 2, wherein the element is a resistance having the resistance valuecorresponding to the type of the lens unit.
 4. A lens unit according toclaim 2, wherein the resistance value is produced by using a linearregion of a switching element such as a transistor or by using asubstrate pattern.
 5. A lens unit according to claim 1, wherein themount includes a second lens terminal for receiving the power supply atthe fourth voltage from the image pickup apparatus.
 6. A lens unitaccording to claim 5, wherein the mount includes a third lens terminalprovided, along with the second lens terminal, for ground connection. 7.A lens unit according to claim 1, wherein the mount includes a fourthlens terminal for receiving, from the image pickup apparatus, a fifthvoltage to be used for drive of an actuator provided in the lens unit.8. A lens unit according to claim 7, wherein the mount includes a fifthlens terminal provided, along with the fourth lens terminal, for groundconnection.
 9. A lens unit according to claim 1, wherein the mountincludes a sixth lens terminal for enabling the image pickup apparatusto detect attachment of the lens unit to the image pickup apparatus. 10.A lens unit according to claim 9, wherein, during a process of theattachment of the lens unit to the image pickup apparatus, electricalcontact of the first lens terminal with a corresponding terminalprovided in the image pickup apparatus is made earlier than electricalcontact of the sixth lens terminal with another corresponding terminalprovided in the image pickup apparatus.
 11. A lens unit according toclaim 1, wherein the mount includes a seventh lens terminal throughwhich the lens controller performs the communication of data with theimage pickup apparatus.
 12. A lens unit comprising: a mount tomechanically couple with an image pickup apparatus and to electricallyconnect the lens unit with the image pickup apparatus; and a lenscontroller configured to receive a power voltage for power source fromthe image pickup apparatus, to produce from the power voltage acommunication voltage different from the power voltage, and to performthe communication with the image pickup apparatus with the communicationvoltage, wherein the mount includes a first lens terminal enablingprovision of a type of the lens unit by a configuration to output apredetermined voltage corresponding to the type of the lens unit in astate of being attached to the image pickup apparatus.
 13. A lens unitaccording to claim 12, wherein the first lens terminal is connected withan element having a resistance value corresponding to the type of thelens unit.
 14. A lens unit according to claim 13, wherein the element isa resistance having the resistance value corresponding to the type ofthe lens unit.
 15. A lens unit according to claim 13, wherein theresistance value is produced by using a linear region of a switchingelement such as a transistor or by using a substrate pattern.
 16. A lensunit according to claim 12, wherein the mount includes a second lensterminal for receiving the power voltage for the lens controller fromthe image pickup apparatus.
 17. A lens unit according to claim 16,wherein the mount includes a third lens terminal provided, along withthe second lens terminal, for ground connection.
 18. A lens unitaccording to claim 12, wherein the mount includes a fourth lens terminalfor receiving, from the image pickup apparatus, a voltage to be used fordrive of an actuator provided in the lens unit.
 19. A lens unitaccording to claim 18, wherein the mount includes a fifth lens terminalprovided, along with the fourth lens terminal, for ground connection.20. A lens unit according to claim 12, wherein the mount includes asixth lens terminal for enabling the image pickup apparatus to detectattachment of the lens unit to the image pickup apparatus.
 21. A lensunit according to claim 20, wherein, during a process of the attachmentof the lens unit to the image pickup apparatus, electrical contact ofthe first lens terminal with a corresponding terminal provided in theimage pickup apparatus is made earlier than electrical contact of thesixth lens terminal with another corresponding terminal provided in theimage pickup apparatus.
 22. A lens unit according to claim 12, whereinthe mount includes a seventh lens terminal through which the lenscontroller performs the communication of data with the image pickupapparatus.